1. Field of the Invention
The present invention relates to materials for depositing antireflective layers, a method for forming resist patterns, and a method for manufacturing semiconductor devices.
2. Description of Related Art
The minimization has been introduced in various industrial fields, and for example in the field of electronic material (including semiconductor devices), the minimum feature size of semiconductor integrated circuit has reached to sub-half micron level.
To meet this need, the technology suitable for highly precise fine works has needed, and corresponding to the expectation, for example, KrF excimer laser lithography has attracted attentions. However, various films used in the process of manufacturing semiconductor devices mostly have high reflectance for light in wavelength region used in this technical field. The high reflectance causes the problem of standing wave effect (multiple interference in a film) and notching due to reflection from steps. For example, the variation of pattern size and pattern distortion are caused. The reflection preventing technology has been developed to avoid these problems, and the technology is categorized into the under coated antireflective layer type and the top coated antireflective layer type. Both types involve advantages and disadvantages, top coated reflection preventing technique using top coated organic layer is useful because of simple process of the technique though the technique is not so effective for notching.
Two types of antireflective layer material for deep ultraviolet, water soluble material and non-water soluble materials, are available commercially. The former is removable directly with resist developing solution in favor of simple processing, but the former mostly has high reflective index and it is difficult to find out a material having ideal refractive index. The latter, non-water soluble antireflective layer material, needs additional peeling process disadvantageously, but ideal refractive index is obtained by using fluoro polymers. Since the factor that the process is simple is considered as important from the view point of manufacturing, however, the former, namely water soluble material, is often selected. As described herein above, the use of the former material cannot result in ideal refractive index, but results in relatively high refractive index. The high refractive index involves the problem of reduced suppression of standing wave effect. In addition, the former material involves the problem of plugging of a pump of waste effluent system when the wast effluent of the former is wasted in the same effluent system that used for resist because the former is water soluble.